octave aborts in save -binary involving a global lazy_index (GCC 4.5)

[Jarno Rajahalme]

Hi,

I have attached a file, with which this problem can be reproduced like follows, 
using the development branch, last updated about two weeks ago. Octave 3.2.3 
built with GCC 4.4 does not exhibit this behavior. I have not yet tried the 
development branch with GCC 4.4.

testing2.oct
Description: Binary data

GNU Octave, version 3.3.51+
[...]
Octave was configured for "x86_64-apple-darwin10.3.0".

[...]

octave:1> load testing2.oct
octave:2> global Testing
octave:3> save -binary testing.oct
terminate called after throwing an instance of 'std::logic_error'
  what():  basic_string::_S_construct NULL not valid
panic: Abort trap -- stopping myself...
attempting to save variables to `octave-core'...
terminate called recursively
panic: attempted clean up apparently failed -- aborting...
Abort trap

The file starts like this:

# Created by Octave 3.3.51+, Thu May 06 22:16:55 2010 PDT <address@hidden>
# name: Testing
# type: global lazy_index
# name: index_value
# type: matrix
# rows: 1
# columns: 1535
 964 1535 219 835 350 1028 498 191 1325 538 488 921 381 504 64 251 624 1464 86 
853 749 764 476 150 1046 1436 6 466 604 1077 39 1350 1052 484 881 1397 277 1396 
1121 ...


gdb backtrace looks like this:


terminate called after throwing an instance of 'std::logic_error'
  what():  basic_string::_S_construct NULL not valid

Program received signal SIGABRT, Aborted.
0x00007fff816eb886 in __kill ()
(gdb) bt
#0  0x00007fff816eb886 in __kill ()
#1  0x00007fff8178beae in abort ()
#2  0x00000001000727a5 in __gnu_cxx::__verbose_terminate_handler ()
#3  0x000000010000516a in __cxxabiv1::__terminate () at 
../../../../gcc-4.5.0/libstdc++-v3/src/parallel_settings.cc:35
#4  0x00000001000051c3 in std::terminate () at 
../../../../gcc-4.5.0/libstdc++-v3/src/parallel_settings.cc:35
#5  0x0000000100005246 in __cxa_throw () at 
../../../../gcc-4.5.0/libstdc++-v3/src/parallel_settings.cc:35
#6  0x000000010001166d in std::__throw_logic_error (__s=<value temporarily 
unavailable, due to optimizations>) at 
../../../../gcc-4.5.0/libstdc++-v3/src/functexcept.cc:62
#7  0x0000000100055761 in std::string::_S_construct<char const*> (__beg=0x0, 
__end=<value temporarily unavailable, due to optimizations>, __a=<value 
temporarily unavailable, due to optimizations>) at basic_string.tcc:133
#8  0x0000000100055873 in basic_string (this=0x7fff5fbfd810, __s=0x0, 
address@hidden) at basic_string.h:1648
#9  0x000000010064ebe8 in octave_lazy_index::save_binary ()
#10 0x00000001003f713e in save_binary_data ()
#11 0x00000001003c558f in do_save ()
#12 0x00000001003c9661 in save_vars ()
#13 0x00000001003cae5b in Fsave ()
#14 0x00000001005a74c1 in octave_builtin::do_multi_index_op ()
#15 0x00000001005a62a7 in octave_builtin::subsref ()
#16 0x00000001006c5e7d in octave_value::subsref ()
#17 0x0000000100798438 in tree_index_expression::rvalue ()
#18 0x000000010078fbd1 in tree_index_expression::rvalue1 ()
#19 0x0000000100779e00 in tree_evaluator::visit_statement ()
#20 0x00000001007774d3 in tree_evaluator::visit_statement_list ()
#21 0x00000001006b2a8d in octave_user_function::do_multi_index_op ()
#22 0x00000001001fe148 in octave_value::do_multi_index_op ()
#23 0x0000000100788dd2 in tree_identifier::rvalue ()
#24 0x0000000100787fba in tree_identifier::rvalue1 ()
#25 0x0000000100779e00 in tree_evaluator::visit_statement ()
#26 0x00000001007774d3 in tree_evaluator::visit_statement_list ()
#27 0x0000000100525420 in main_loop ()
#28 0x00000001004b8819 in octave_main ()
#29 0x0000000100000f44 in start ()
(gdb) 

Relevant part of GCC 4.5 basic_string.tcc:
   template<typename _CharT, typename _Traits, typename _Alloc>
    template <typename _InIterator>
      _CharT*
      basic_string<_CharT, _Traits, _Alloc>::
      _S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a,
                   forward_iterator_tag)
      {
#ifndef _GLIBCXX_FULLY_DYNAMIC_STRING
        if (__beg == __end && __a == _Alloc())
          return _S_empty_rep()._M_refdata();
#endif
        // NB: Not required, but considered best practice.
        if (__gnu_cxx::__is_null_pointer(__beg) && __beg != __end)
          __throw_logic_error(__N("basic_string::_S_construct NULL not valid"));


The check on the last three lines does not appear on Apple's version of GCC 4.2.


basic_string.h on and around the line indicated:

      template<class _InIterator>
        static _CharT*
        _S_construct_aux(_InIterator __beg, _InIterator __end,
                         const _Alloc& __a, __false_type)
        {
          typedef typename iterator_traits<_InIterator>::iterator_category _Tag;
          return _S_construct(__beg, __end, __a, _Tag());
        }


So it appears that GCC 4.5 has added some checks for invalid data, that now 
triggers with lazy_index in binary mode. Ascii saving works, but I'd prefer 
binary...

Regards,

  Jarno